On TVNZ's Breakfast this morning Mr Key defended his decision to take part in the game.

Asked about the link between games like beer pong and irresponsible drinking, Mr Key said: "I've heard those sorts of things before. I mean look, it was a bit of fun. It was about that much beer [about an inch] in the cups, so it wasn't anything too crazy."

Mr Key added it was "in the spirit of a bit of fun".

He said he would "definitely win" a game of beer pong against Labour leader David Cunliffe.